Method of making and dispensing nitrogen-charged coffee

ABSTRACT

A method of making coffee is provided. After a cold-brewed coffee is extracted from coffee beans, nitrogen gas is charged into the cold-brewed coffee. The cold-brewed coffee into which nitrogen gas is dissolved, is cooled to form a nitrogen-charged coffee. Therefore, the nitrogen-charged coffee may keep a rich density of foam and a flavor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC §119 to Korean PatentApplication No. 10-2014-0086750 filed on Jul. 10, 2014, the contents ofwhich are herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Example embodiments of the present invention relate to a method ofmaking coffee and an apparatus of making coffee. More particularly,example embodiments of the present invention relate to a method ofmaking coffee capable of keeping flavor at a relatively low temperatureand an apparatus of making coffee realizing the method.

2. Description of the Related Art

Generally, one example of iced coffee is Iced Americano, which has beenwidely sold in coffee shops. The Iced Americano is made by dilutingEspresso with water and ice, which is extracted from ground coffee usinga relatively high pressure. However, the Iced Americano is made byadding cold water and ice to Espresso having a crema of minute foam andhaving velvety texture and a form layer, which may cause a temperatureof Iced Americano lower to enhance bitter taste and to deterioratetexture dramatically by breaking the foam layer.

Thus, it has been required for iced coffee to keep a density of foamrich and maintain texture.

SUMMARY OF THE INVENTION

Example embodiments of the present invention provide a method of makinga coffee capable of keeping a rich density of form and a flavor.

Example embodiments of the present invention provide an apparatus ofmaking a coffee capable of keeping a rich density of form and a flavor.

According to one aspect of the present invention, there is provided amethod of making coffee. After a cold-brewed coffee is extracted fromcoffee beans, nitrogen gas is charged into the cold-brewed coffee. Thecold-brewed coffee into which nitrogen gas is dissolved, is cooled toform a nitrogen-charged coffee. Here, in order to extract thecold-brewed coffee form the coffee beans, the coffee beans is grinded toform a ground coffee. The ground coffee is steeped into water to form amixture having the ground coffee and water. Then, after an extractedcoffee is extracted from the mixture, the extracted coffee is dilutedwith water.

In an example embodiment, a concentration (TDS) of the cold-brewedcoffee is in a range from about 1.36% to about 1.58%.

In an example embodiment, dispensing the nitrogen-charged coffee into acup may be further performed. Here, in order to dispense thenitrogen-charged coffee into the cup, the nitrogen-charged coffee isdischarged from a nozzle and then nitrogen gas is additionallydischarged from the nozzle while discharging the nitrogen-chargedcoffee.

According to one aspect of the present invention, there is provided a Anapparatus of making coffee. The apparatus includes a keg storing acold-brewed coffee, a nitrogen tank containing nitrogen gas, thenitrogen tank being connected with keg by a first line to be configuredto provide nitrogen gas with the keg to form a nitrogen-charged coffee,a discharging unit being connected with the keg by a second line to beconfigured to discharge the nitrogen-charged coffee, and a first coolingunit covering the second line to be configured to cool thenitrogen-charged coffee.

In an example embodiment of the present invention, the apparatus mayfurther include a third line connecting the nitrogen tank with thedischarge unit, the discharging unit may be configured to selectivelyopen/close the second line and the third line to selectively dischargethe nitrogen-charged coffee or to discharge the nitrogen-charged coffeeand nitrogen gas at the same time.

In an example embodiment of the present invention, the apparatus mayfurther include a second cooling unit receiving the keg, the secondcooling unit being configured to cool the cold-brewed coffee in the keg.

In an example embodiment of the present invention, an internal pressureof nitrogen gas in the keg is in a range of about 6.0 bar to about 6.5bar.

In an example embodiment of the present invention, the discharging unitincludes a nozzle and a lever to be configure to selectively open/closethe nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detailed exemplaryembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a flow chart illustrating a method of making coffee inaccordance with an example embodiment of the present invention;

FIG. 2 is a flow chart illustrating a step of extracting a cold-brewedcoffee in FIG. 1; and

FIG. 3 is a cross-sectional view illustrating an apparatus of makingcoffee in accordance with an example embodiment of the presentinvention.

DESCRIPTION OF THE EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the inventionto those skilled in the art. In the drawings, the sizes and relativesizes of layers and regions may be exaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numbers refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present invention.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Embodiments of the invention are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the invention. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the invention should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing. For example, an implanted region illustrated as arectangle will, typically, have rounded or curved features and/or agradient of implant concentration at its edges rather than a binarychange from implanted to non-implanted region. Likewise, a buried regionformed by implantation may result in some implantation in the regionbetween the buried region and the surface through which the implantationtakes place. Thus, the regions illustrated in the figures are schematicin nature and their shapes are not intended to illustrate the actualshape of a region of a device and are not intended to limit the scope ofthe invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is a flow chart illustrating a method of making coffee inaccordance with an example embodiment of the present invention.

Referring to FIG. 1, a method of making coffee according to exampleembodiment of the present invention will be explained in detail.

At first, a cold-brewed coffee is extracted from coffee beans (stepS110).

The cold-brewed coffee is formed by brewing the coffee beans in water,for example, a purified water at a relatively low temperature.

FIG. 2 is a flow chart illustrating a step of extracting a cold-brewedcoffee in FIG. 1.

Referring to FIG. 2, the coffee beans is grinded under a pressure toform a ground coffee (step S111).

The ground coffee has powders each having an average grind size of about800 μm to about 900 μm. More particular, the average grind size may bein a range of about 840 μm to about 860 μm. Preferably, the averagediameter of the ground coffee is about 850 μm.

When the ground coffee has the powders each having an average grind sizeless than 800 μm, the ground coffee may be too over-extracted. Thus, thecold-brewed coffee may taste stale or bitter.

When the ground coffee has the powders each having an average diametermore than 900 μm, the ground coffee may be too under-extracted. Thus,the cold-brewed coffee may taste watery or plain.

Next, the ground coffee is steeped in water, for example, a purifiedwater at a relatively low temperature (step S112). Thus, a mixturehaving the ground coffee and the water is formed.

A ratio of the ground coffee with respect to water may be in a range ofabout 180 g/L to about 195 g/L. Further, water may be controlled to havea temperature of about 10° C. to about 15° C. and a steeping time may befrom about 12 hours to about 24 hours. The steeping time may be adjustedaccording to characteristics of the coffee beans, which may vary inaccordance with each origin of the coffee beans, and a roasting degreeof the coffee beans.

A range of water hardness is between about 100 ppm and about 200 ppm.When water have the water hardness of less than 100 ppm, the cold-brewedcoffee may taste weak flavor, even though the cold-brewed coffee tastesmild and have an improved acidity.

When water have the water hardness of more than 200 ppm, the cold-brewedcoffee may taste sharply bitter, stale such that the cold-brewed coffeemay not be smooth.

Thus, when the water has the water hardness of between about 100 ppm andabout 200 ppm, the cold-brewed coffee may have balanced taste ofsweetness, acidity and bitterness.

When the ratio of the ground coffee with respect to water is less than180 g/L or the steeping time is less than 12 hours, the ground coffeemay be too under-extracted while brewing the ground coffee such that thecold-brewed coffee may taste watery or plain.

In contrast, when the ratio of the ground coffee with respect to wateris more than 195 g/L or the steeping time is over 24 hours, the groundcoffee may be over-extracted while brewing the ground coffee such thatthe cold-brewed coffee may taste stale or bitter.

An extracted coffee is extracted from the mixture having the groundcoffee and water (step S113).

In particularly, the mixture passes through a filtering sheet to removethe ground coffee having a relatively large size from the mixture toform the extracted coffee.

The extracted coffee is diluted with water to form a cold-brewed coffee(step S114).

The extracted coffee is attenuated with water to form the cold-brewedcoffee having a concentration suitable for drinking. A concentration ofTDS in the cold-brewed coffee against water is in a range of about 1.36%to about 1.58%. The TDS is an abbreviation of total dissolved solids,which means a weight of the TDS in the cold-brewed coffee.

When the concentration of the cold-brewed coffee is less than 1.36%, thecold-brewed coffee may taste watery or plain. Further, the cold-brewedcoffee may not have a balanced taste. In contrast, when theconcentration of the cold-brewed coffee is more than 1.58%, thecold-brewed coffee may taste excessively bitter or have a taste toostrong to drink.

Further, a volume ratio between the extracted coffee and water may be ina range of about 1:0.8 to about 1:1.2. Water may include heavy waterhaving a water hardness of about 100 ppm to about 200 ppm.

When the volume ratio is less than about 1:0.8, an amount of water istoo little, whereas the concentration of the cold-brewed coffee is toohigh. Thus, the cold-brewed coffee may taste too bitter or have a badbalanced taste too strong to drink.

When the volume ratio is more than about 1:0.2, an amount of water istoo much, whereas the concentration of the cold-brewed coffee is toolow. Thus, the cold-brewed coffee may taste watery or may not have abalanced taste.

Water is mixed to the extracted coffee to control an amount of thecold-brewed coffee easily. Thus, cost for making the cold-brewed coffeemay decrease to improve an productivity of making the cold-brewedcoffee. Further, the volume ratio between the extracted coffee and watermay be easily adjusted to control the concentration of the cold-brewedcoffee. So, a standard of taste related to the cold-brewed coffee may beestablished conveniently.

In another example embodiment, the extracted coffee may be utilizedwithout diluting the extracted coffee with water. In other words, theconcentration of the extracted coffee (TSD) may be adjusted in a rangeof about 1.36% to about 1.58% to omit a step of diluting the extractedcoffee with water.

The cold-brewed coffee may be stored in a keg. The keg may be occupiedwith nitrogen gas. Thus, the cold-brewed coffee may be prevented fromreacting with oxygen gas and from being oxidized.

The cold-brewed coffee may be stored at a temperature of about 1° C. toabout 10° C.

When the cold-brewed coffee is stored at a temperature of less than 1°C., the cold-brewed coffee may be frozen. Further, when the cold brewedcoffee is stored at a temperature of more than 10° C., the cold-brewedcoffee may be lukewarm to a mouth or may have a degraded refreshingtaste.

Referring to FIG. 1 again, nitrogen gas is charged into the cold-brewedcoffee (step S120).

In particular, nitrogen gas is bubbled in the cold-brewed coffee storedin the keg to charge nitrogen gas into the cold-brewed coffee. In orderto perform charging nitrogen gas into the cold-brewed coffeeefficiently, nitrogen gas may be repeatedly provided into thecold-brewed coffee. For example, nitrogen gas may charged into thecold-brewed coffee two times. Further, a pressure of nitrogen gas is ina range of about 6.0 bar to about 6.5 bar in the keg.

When the pressure of nitrogen gas is less than about 6.0 bar, thepressure of nitrogen gas is too low to charge nitrogen gas into thecold-brewed coffee sufficiently. Thus, the nitrogen charged coffee to beformed by charging nitrogen gas into the cold-brewed coffee, may notgenerate micro-sized foams. In the meantime, when the pressure ofnitrogen gas is more than about 6.5 bar, the pressure of nitrogen gas istoo high, which may cause a nitrogen-providing unit malfunctioned.

Next, the cold-brewed coffee in which nitrogen gas is dissolved, iscooled to form a nitrogen-charged coffee. Nitrogen gas is provided inthe keg to increase a pressure of nitrogen gas in the keg to supply thecold-brewed coffee into a discharging unit.

While the cold-brewed coffee is drained out from the keg to thedischarging unit, the cold-brewed coffee in which nitrogen gas isdissolved may be cooled to have a predetermined temperature. Forexample, the predetermined temperature is from about 1° C. to about 10°C. More particularly, the temperature is in a range of about 3° C. toabout 6° C. More preferably, the temperature is about 4° C.

When the temperature is less than 1° C., the cold-brewed coffee in whichnitrogen gas is dissolved may be frozen. Meanwhile, when the temperatureis more than 10° C., the cold-brewed coffee in which nitrogen gas isdissolved may be lukewarm in a mouth or may have a degraded refreshingtaste. Thus, the cold-brewed coffee in which nitrogen gas is dissolved,may have a rich flavor, a good density of foam, a balanced taste, a goodtexture, etc.

The nitrogen-charged coffee is discharged into a cup (step S140).

The nitrogen-charged coffee is discharged from a nozzle into the cup.When the nitrogen-charged coffee is discharged from the nozzle,micro-sized foams may generated at a surface of the nitrogen-chargedcoffee due to nitrogen gas. The micro-sized foams may form a foam layeron the surface of the nitrogen-charged coffee. The foam layer may bemaintained on the surface for a period of time to cover thenitrogen-charged coffee. Thus, the nitrogen-charged coffee may maintaina smooth and rich texture, a concentration of foam and a flavor untilthe nitrogen-charged coffee is drunken up.

In example embodiment of the present invention, after partially fillingthe cup with the nitrogen-charged coffee, the nitrogen-charged coffeeand nitrogen gas may be discharged simultaneously from the nozzle tofill the cup additionally. Thus, the nitrogen-charged coffee dispensedinto the cup may have rich foam on a top thereof. As a result, thenitrogen-charged coffee have the foam layer thick. Here, a volume of thenitrogen-charged coffee which firstly fills the cup, is defined as afirst volume. Further, a volume of the nitrogen-charged coffee andnitrogen gas which are discharged simultaneously from the nozzle, isdefined as a second volume.

A volume ratio of the first volume with respect to an overall volume ofthe nitrogen-charged coffee in the cup, may be in a range of about 60%to about 80%.

When the volume ratio is less than about 60%, the second volume may beexcessively high. Thus, the foam layer may be too thick, which may causeinconvenience that coffee-drinker's mouth is smeared with foam of thenitrogen-charged coffee.

When the volume ratio is more than about 80%, the first volume may beexcessively high. Thus, the foam layer formed around a upper surface ofthe nitrogen-charged coffee may be too thin.

FIG. 3 is a cross-sectional view illustrating an apparatus of makingcoffee in accordance with an example embodiment of the presentinvention.

Referring to FIG. 3, an apparatus 100 of making coffee in accordancewith an example embodiment of the present invention includes a keg 110,a nitrogen tank 120, a first line 130, a discharging unit 140, a secondline 150, a first cooling unit 160, a third line 170 and a secondcooling unit 180.

The keg 110 stores a coffee 10 therein. The keg 110 is filled withnitrogen gas. Thus, the cold-brewed coffee 10 may be prevented frombeing reacted with oxygen and being oxidized.

The coffee 10 may include a cold-brewed coffee. For example, the coffee10 may include the cold-brewed coffee made by a method of making thecold-brewed coffee explained with FIG. 2

The nitrogen tank 120 stores nitrogen gas therein. The nitrogen tank 120is connected to the keg 110 by the first line 130. The first line 130may extend such that a end portion of the first line 130 is dipped intothe coffee 10 of the keg 110.

Nitrogen gas is provided from the nitrogen tank 120 into the keg 110through the first line 130. In particular, nitrogen gas is bubbled inthe coffee 10 to be dissolved in the coffee 10. Thus, a nitrogen-chargedcoffee may be formed in the keg 110. In order to efficiently dissolvenitrogen gas in the coffee 10, nitrogen gas may be repeatedly providedinto the coffee 10. For example, nitrogen gas is provided into thecoffee 10 two times.

The nitrogen tank 120 may keep an internal pressure of nitrogen gasbetween about 6.0 bar to about 6.5 bar.

When the internal pressure is less than about 6.0 bar, nitrogen gas maynot be efficiently dissolved in the coffee 10 such that micro-sized foammay not occur to the coffee 10. when the internal pressure is more thanabout 6.5 bar, the pressure of nitrogen gas is too high, which may causethe nitrogen tank 120 or the first line 130 malfunctioned.

The discharging unit 140 is configured to discharge the nitrogen-chargedcoffee. The discharging unit 140 may include a nozzle 142 and a lever144. The lever 144 may selectively open/close the nozzle 142 todetermine whether the nitrogen-charged coffee is discharged or not. Thenozzle 142 may be a passway by which the nitrogen-charged coffee isdischarged. Alternatively, the lever 144 may selectively open/close thesecond line 150 to determine whether the nitrogen-charged coffee isdischarged or not.

The discharging unit 140 is connected with the keg 110 by the secondline 150. The second line 150 may extend such that a end portion of thesecond line 150 is dipped into a low portion of the keg 110.

Due to the internal pressure of nitrogen gas in the keg 110, thenitrogen-charged coffee may flow to the discharging unit 140 by thesecond line 150.

The first cooling unit 160 surrounds the second line 150. The firstcooling unit 160 may circulate cooling water along the second line 150to cool the nitrogen-charged coffee which flows through the second line150. Thus, the nitrogen-charged coffee may be supplied into thedischarging unit 140 with keeping a temperature of the nitrogen-chargedcoffee constant.

Even thought not shown in FIG. 3, the first cooling unit 160 may includea circulating line serving as a passway for cooling water, pump forcirculating cooling water and a chiller for chilling cooling water tocool the nitrogen-charged coffee at a predetermined temperature.

For example, the predetermined temperature is from about 1° C. to about10° C. More particularly, the temperature is in a range of about 3° C.to about 6° C. More preferably, the temperature is about 4° C.

When the first cooling unit 160 may cool the nitrogen-charged coffeehaving a temperature of less than 1° C., the nitrogen-charged coffee maybe frozen to plug the second line 150. Meanwhile, when the first coolingunit 160 may cool the nitrogen-charged coffee having a temperature ofmore than 10° C., the nitrogen-charged coffee may be lukewarm in a mouthor may have a degraded refreshing taste. Thus, the nitrogen-chargedcoffee may have a rich flavor, a good density, a good acidity, a goodtexture, etc.

In some example embodiments of the present invention, the apparatus 100further includes a third line 170. The third line 170 may connect thenitrogen tank 120 to the discharging unit 140. In particular, the thirdline 170 may connect the nitrogen tank 120 to the nozzle 142 of thedischarging unit 140. The nozzle 142 may be a passway by which nitrogengas is discharged. The lever 144 may selectively open/close the secondline 150 and the third line 170 to determine whether thenitrogen-charged coffee is discharged and whether nitrogen gas isdischarged. Thus, the discharging unit 140 may dispense only thenitrogen-charged coffee or dispense both the nitrogen-charged coffee andnitrogen coffee simultaneously through the nozzle 142, depending on anoperation of the lever 144

When the lever 144 is positioned at a center, the second line 150 andthe third line 170 is kept to be close. When the lever 144 is pulledforwardly, the third line 170 is kept to be close and the second line150 changes to be open such that the nitrogen-charged coffee isdischarged from the nozzle 142 through the second line 150. When thelever 144 is pushed backwardly, both the third line 170 and the secondline 150 change to be open such that the nitrogen-charged coffee andnitrogen gas are simultaneously discharged from the nozzle 142 throughthe second line 150 and the third line 170, respectively.

When the nitrogen-charged coffee is discharged from the nozzle 142 to beprovided into a cup, micro-sized foam may be formed on an upper surfaceof the nitrogen-charged coffee due to nitrogen gas which is dissolved inthe nitrogen-charged coffee. Thus, the foam layer is formed on the uppersurface of the nitrogen-charged coffee.

When the nitrogen-charged coffee and nitrogen gas are simultaneouslydischarged from the nozzle 142, micro-sized foam may be affluentlyformed on an upper surface of the nitrogen-charged coffee due to bothnitrogen gas which is dissolved in the nitrogen-charged coffee andnitrogen gas additionally discharged from the nozzle 142. Thus, the foamlayer becoming thicker is formed on the upper surface of thenitrogen-charged coffee.

When the nitrogen-charged coffee and nitrogen gas are simultaneouslydischarged from the nozzle 142, the foam layer may be excessively thickon the upper surface of the nitrogen-charged coffee. Thus, it may benecessary to adjust a ratio between a volume of the nitrogen-chargedcoffee which is supplied only through the second line 150 and a volumeof nitrogen gas and a volume of the nitrogen-charged coffee and nitrogengas which are simultaneously discharged from the nozzle 142 in order tocontrol a thickness of the foam layer.

The foam layer may be maintained on the surface for a period of time tocover the nitrogen-charged coffee. Thus, the nitrogen-charged coffee maykeep a smooth texture, a concentration and a flavor until thenitrogen-charged coffee is drunken up.

Even thought not shown in FIG. 3, the first line 130, the second line150 and the third line 170 may include valves, respectively. The firstline 130, the second line 150 and the third line 170 may be selectivelyopen/close depending on an operation of the valves.

The second cooling unit 180 is configured to receive the keg 110. Thesecond cooling unit 180 cools the nitrogen-charged coffee stored in thekeg 110. The second cooling unit 180 may include a refrigerator.

The second cooling unit 180 may chill the nitrogen-charged coffee havinga temperature, as the first cooling unit 160 does. The second coolingunit 180 may chill the nitrogen-charged coffee having a temperature fromabout 1° C. to about 10° C.

When an excessively large amount of the nitrogen-charged coffee isdischarged from the discharging unit 140, the first cooling unit 160 maynot be capable of cooling the nitrogen-charged coffee efficiently. Thus,the second cooling unit 180 may chill the nitrogen-charged coffee beforeproviding nitrogen-charged coffee into the discharging unit 140 in orderto assist the first cooling unit 160. Thus, even though an large amountof the nitrogen-charged coffee is discharged from the discharging unit140, the nitrogen-charged coffee may be discharged under a cooledstatus. As a result, the nitrogen-charged coffee may be prevented frombeing lukewarm in a mouth or degrading a refreshing taste.

According to example embodiments of the present invention, nitrogen gasis bubbled in a cold-brewed coffee to form a nitrogen-charged coffee,After discharging the nitrogen-charged coffee, a foam layer having athickness may be formed on an upper surface of the nitrogen-chargedcoffee and the foam layer may be maintained for a period of time. Thus,the nitrogen-charged coffee may keep a smooth texture, a concentrationand a flavor until the nitrogen-charged coffee is drunken up.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the present invention. Accordingly, all such modificationsare intended to be included within the scope of this invention asdefined in the claims. In the claims, means-plus-function clauses areintended to cover the structures described herein as performing therecited function and not only structural equivalents but also equivalentstructures. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the appended claims. The invention isdefined by the following claims, with equivalents of the claims to beincluded therein.

What is claimed is:
 1. A method of making coffee comprising: extractinga cold-brewed coffee from coffee beans, the cold-brewed coffee beingstored in a keg which is occupied with nitrogen gas; charging nitrogengas into the cold-brewed coffee by bubbling the nitrogen gas in thecold-brewed coffee stored in the keg; cooling the cold-brewed coffeeinto which the nitrogen gas is dissolved to form a nitrogen-chargedcoffee; and dispensing the nitrogen-charged coffee into a cup, whereindispensing the nitrogen-charged coffee into the cup comprises:discharging the nitrogen-charged coffee from a nozzle to partially fillthe cup; and additionally discharging nitrogen gas from the nozzle whiledischarging the nitrogen-charged coffee to fill the cup additionally. 2.The method of making coffee of claim 1, wherein extracting thecold-brewed coffee from the coffee beans comprises: grinding the coffeebeans to form a ground coffee; steeping the ground coffee into water toform a mixture having the ground coffee and water; partially extractingan extracted coffee from the mixture; and diluting the extracted coffeewith water.
 3. The method of making coffee of claim 1, wherein aconcentration of total dissolved solids in the cold-brewed coffee is ina range from about 1.36% to about 1.58%.